AFC mod...attepted, may have missed something
 

Ok, so I started about 1pm today and I got the AFC housing off pretty easily. The breakaway wasn't bad it was the slotted one that gave me trouble. Anyway took that off and pulled fuel plate. I ground a #100 profile (flat with a radius at the bottom) into the plate and re-installed with it slid toward the front of the engine. My star wheel was already basically turned all the way touching the housing. Then I shaved about 1/8 in off the AFC foot shaft. I turned the "smoke screw" so that when the 2 bolt (one breakaway) access plate is removed that the threaded shaft with the internal allen head is almost flush with the jam nut. I did NOT replace the cups on the diaphram with washers because I didn't quite understand what was going on there. So I get her all back together and was thinking that what I had done would give me some more power and smoke but I didn't notice power changes and still...no smoke. And I know smoke is unburn/wasted fuel but I want it to kick some out, I got nothing. What did I do wrong? Any help would be great. thank you

I went out removed the silencer ring and noticed some debris in the inlet, then I found out why, I cant believe I never checked it, what a dummy:argh:, well I got some pics of the star wheel and AFC still no smoke though...

http://www.dieselbombers.cohttps://w...1&d=1352094170

the barrel of the foot or the blade of the foot? did you tune the afc as a unit with compressed air? you should have or all you did is totally screw the factory tune out of your pump. absolute best bang for your buck is a set of govenor springs. they will totally turn your truck into a different creature. a fuel plate wont give you that OMG my truck is so fast feeling AT ALL! you need supporting mods to notice much of any gain from a plate. a #6 was my first mod back in the day. a big $225 let down. but after much more extensive piddling with the truck i found it to be my best plate for daily driving until lately.

I shaved down the round part that the shaft slides into. No, I didn't use air, the wheel was already fully towards the front of the truck. I just figured I'd get more power/smoke for free, I just really don't see any difference at all. I want to get all the free stuff done first...and right then its the 4k GSK/60lb springs, 2095 plug and boost elbow for starters

well it sounds like you need to do your afc all over again. tune it this time just dont screw with the little wheels and ahinny things. LOL it will run better. do the washer flip so you get the extra bit of travel. it takes like 10 min to do if the afc is already in your hand. then use regulated air to tune the afc. i would buy an boost elbow and tune the afc for the mid 30's boost. if not you will be tuning again when you install the elbow. the rack plug only gives you a WOT increase.

I was just under the impression that if I turned the wheel all the way forward that it would fuel up no matter what boost was at, Im slowly wrapping my head around this stuff. Now those washers, the one that the spring seated in was cupped, with the cup going over the spring and then on the other side of the diaphram was just a flat type. So I can ditch both of those and replace with 2 washers? Is there a specific size or P/N so I get the right ones? Also is the rubber diaphram directional?

you can just grind the cup off the one washer and yes. there is a really good right up somewhere floating around here on the AFC

hope this helps

http://www.dieselram.com/showthread.php?t=184064

Ok, well it looks like the AFC is coming off again, ill grab some washers and a filter today at the parts store. What exactly does replacing the washers do? I really appreciate all the info!!

The lip on the Large forward cup bottoms out on the body of the AFC. Flipping them allows more inward travel.


To further explain the mechanism and its function....

The starwheel applies preload on the diaphragm. So when its farthest forward, there is the least amount of preload on the diaphragm. So less boost pressure will push the mechanism forward priming the fueling rail.


Black smoke is fuel the engine does not have the heat to burn... so its just further cooling your flame kernal, producing less energy.


So using air pressure allows you to time where your fueling rod dumps in, accelerating your fueling curve to match boost pressure.

Think of it as a Giant accelerator pump on a carburetor.

Technically, I think the "smoke screw" is the accelerator pump, allowing more mechanically applied fuel regardless of air flow to get things going, and the AFC is more of a vacuum secondary wich regulates fuel per air flow, if we're comparing injection pumps to carbs... :w2: